In particular, the invention relates to a method for detecting and controlling in a closed loop the uneven running of an IC engine. A control device embodying a method of this type, which typically exists with modern vehicles, is e.g. also known as Engine Smoothness Control (ESC). Many cases of engine smoothness control systems of this type are known, so that the design and functionality of the different, known engine smoothness control systems is not explained in detail hereinafter.
Based on the unavoidable existence of process tolerances of the injection system as well as by the occurring ageing effects different fuel quantities are proportioned to the cylinders.
Even minor differences of the fuel quantities supplied to the cylinders result in torque variations, what may be the cause of unwanted vibrations for examples of mirrors, steering wheels and the like. Such vibrations have a particular unwanted influence in case of the IC engine of the motor vehicle, as here the engines are often rocked, which must be taken into consideration when dimensioning the engine construction, as this may possibly have a negative impact on the life time of the engine. Moreover, the above mentioned differences in the injected fuel quantity have an unfavorable influence on the noise, the life time and on the emissions of the IC engine. It is understandably essential to avoid these unwanted influences.
The above mentioned torque variations are reflected for instance in the instantaneous crankshaft speed and in the instantaneous crankshaft acceleration, which can be measured and analyzed in the engine control device.